Finding the Third Proportional to 289,986 and 443,645

Step by Step Solution

1. Step 1: Write the proportion equation
   289,986 : 443,645 = 443,645 : x
2. Step 2: Convert to fraction form
   289,986/443,645 = 443,645/x
3. Step 3: Cross multiply
   289,986x = 443,645 × 443,645
4. Step 4: Simplify right side
   289,986x = 196,820,886,025
5. Step 5: Solve for x
   x = 196,820,886,025/289,986
6. Step 6: Final answer
   x = 678,725.48